1. Field of the Invention
The present invention relates to a communication device and a method used in a wireless communication system, and more particularly, to a communication device and method of handling a radio resource control (RRC) connection resume procedure.
2. Description of the Prior Art
When performing a RRC connection resume procedure, an EMM layer of a UE may only provide a RRC establishment cause and a call type to a RRC layer of the UE. Then, the RRC layer transmits a RRC connection resume request message to a network. The network may transmit a RRC connection setup message to the UE. However, the RRC layer cannot transmit a RRC connection setup complete message to the network for responding to the RRC connection setup message, because the RRC layer has not received information from the EMM layer. In this situation, it is unknown how to handle the RRC connection setup complete message. Accordingly, the RRC connection resume procedure cannot be performed successfully.
Thus, how to handle the RRC connection resume procedure is an important problem to be solved.